1. Field of the Invention
The field of the present invention is that of repairs to aeronautical engines and, more particularly, that of repairs to multi-lip scalloped casing flanges.
2. Description of the Related Art
Aeronautical engines are generally made up of an assembly of modules which are formed, in terms of their external part, by a series of casings aligned one after the other along the axis of rotation of the engine. These casings are assembled by bolts which pass through holes made in flanges which run radially at the longitudinal ends of the casings. These flanges are generally scalloped in order to reduce their mass and keep material only in the region of the assembly holes. They are also used to support the equipment needed for the operation of the engine, which equipment is positioned on the outside of this engine. Equipment supports are thus regularly bolted to the holes made in the flanges.
Because of engine vibrations which excite this equipment and because of the relatively high mass of such equipment, it is found, firstly, that the holes begin to ovalize and secondly that the scallop lips, subjected to fatigue loading, ultimately crack and then even break. This then compromises the retention of the equipment concerned.
Using weld material to build up aluminum-based alloy casings does not restore mechanical properties equivalent to those of the unrepaired component. The repair solutions generally proposed involve leveling of the damaged part and absorbing its loadings through a reinforcing piece which is fastened to the remaining healthy scallop lips situated on each side of the leveled-off lip.
Current repair solutions rely on kits, or sets of components, which are specific and each suited to the repair of a specifically defined design of multi-lip scallop. It therefore follows that the repairer has to have a great many items in stock to suit the various possible types of multi-lipped scallop that need repairing.
Also known is a device for fastening an aeronautical engine accessory to one of its flanges, as described in document U.S. Pat. No. 3,155,352. This involves fastening an accessory to a healthy flange of the engine and provides no teaching as to how to repair a damaged flange.